const enum GyroSensorMode {
    None = -1,
    Angle = 0,
    Rate = 1,
}

namespace sensors {
    //% fixedInstances
    export class GyroSensor extends internal.UartSensor {
        private calibrating: boolean;
        constructor(port: number) {
            super(port)
            this.calibrating = false;
        }

        _deviceType() {
            return DAL.DEVICE_TYPE_GYRO
        }

        setMode(m: GyroSensorMode) {
            this._setMode(m)
        }

        /**
         * Get the current angle from the gyroscope.
         * @param sensor the gyroscope to query the request
         */
        //% help=input/gyro/angle
        //% block="%sensor|angle"
        //% blockId=gyroGetAngle
        //% parts="gyroscope"
        //% blockNamespace=sensors
        //% sensor.fieldEditor="ports"
        //% weight=64 blockGap=8
        //% group="Gyro Sensor"
        angle(): number {
            if (this.calibrating)
                pauseUntil(() => !this.calibrating, 2000);

            this.setMode(GyroSensorMode.Angle)
            return this.getNumber(NumberFormat.Int16LE, 0)
        }

        /**
         * Get the current rotation rate from the gyroscope.
         * @param sensor the gyroscope to query the request
         */
        //% help=input/gyro/rate
        //% block="%sensor|rate"
        //% blockId=gyroGetRate
        //% parts="gyroscope"
        //% blockNamespace=sensors
        //% sensor.fieldEditor="ports"
        //% weight=65 blockGap=8        
        //% group="Gyro Sensor"
        rate(): number {
            if (this.calibrating)
                pauseUntil(() => !this.calibrating, 2000);

            this.setMode(GyroSensorMode.Rate)
            return this.getNumber(NumberFormat.Int16LE, 0)
        }

        /**
         * Forces a calibration of the gyro. Must be called when the sensor is completely still.
         */
        //% help=input/gyro/calibrate
        //% block="%sensor|reset"
        //% blockId=gyroReset  
        //% parts="gyroscope"
        //% blockNamespace=sensors
        //% sensor.fieldEditor="ports"
        //% weight=50 blockGap=8        
        //% group="Gyro Sensor"
        reset(): void {
            if (this.calibrating) return; // already in calibration mode

            this.calibrating = true;
            // may be triggered by a button click, give time to settle
            loops.pause(500);
            // send a reset command
            super.reset();
            // we need to switch mode twice to perform a calibration
            if (this.mode == GyroSensorMode.Rate)
                this.setMode(GyroSensorMode.Angle);
            else
                this.setMode(GyroSensorMode.Rate);
            // switch back and wait
            if (this.mode == GyroSensorMode.Rate)
                this.setMode(GyroSensorMode.Angle);
            else
                this.setMode(GyroSensorMode.Rate);
            // give it more time to settle
            loops.pause(500);
            this.calibrating = false;            
        }
    }

    //% fixedInstance whenUsed block="gyro 2" weight=95 jres=icons.port2
    export const gyro2: GyroSensor = new GyroSensor(2)

    //% fixedInstance whenUsed block="gyro 1" jres=icons.port1
    export const gyro1: GyroSensor = new GyroSensor(1)

    //% fixedInstance whenUsed block="gyro 3" jres=icons.port3
    export const gyro3: GyroSensor = new GyroSensor(3)

    //% fixedInstance whenUsed block="gyro 4" jres=icons.port4
    export const gyro4: GyroSensor = new GyroSensor(4)
}